This invention relates to a method of processing photographic material. In particular the invention relates to a method of processing which uses a low volume of processing solution and which provides images of non-varying quality.
The processing of photosensitive material such as photographic film involves a series of steps such as developing, bleaching, fixing, washing and drying. In this process a continuous web of film or cut sheet of film is sequentially conveyed through a series of stations or tanks, with each one containing a different processing solution appropriate to the process step at that stage.
When using small volumes to process a film the chemicals slowly exhaust themselves and lose activity. This can lead to unacceptable processing variations along the length of the film. It is important to maintain the activity of the process to give repeatable results and match manufacturer""s specifications.
To achieve repeatable results for the C41 process the temperature must be held constant to +0.15xc2x0 C. and fresh chemistry must be added to the bath or tank to maintain steady chemical activity.
Work has been done on this in the past. EP 694,815 shows that temperature can be used to compensate for the activity loss during colour paper processing but in this instance to yield a fixed sensitometric result. The availability of digital image processing allows the image to be corrected from what otherwise would be a uncorrectable image in a optical print system if information is known about the current state of the process.
With the advent of digital scanning lower image contrast can be tolerated and this has led to the use of smaller volumes of chemistry in the tanks and the reduction of process times. New processing methods using single shot and batch non-replenished systems have led to the use of volumes that are at or approaching the manufactures typical replenishment volumes (4-6 ml/ft).
However, without the benefit of the large volumes held in conventional processors smoothing sensitometric changes, unacceptable results are obtained even with scanning. This can be seen in FIG. 2 of the accompanying drawings. It is an aim of the invention to provide a method of processing which gives acceptable results with very low volumes of processing solution.
According to the present invention there is provided a method of processing photosensitive material comprising passing the material through at least one processing chamber containing processing solution, the volume of the solution being less than 1000 ml, and raising the temperature of the solution as the material passes through the chamber, the rate of temperature increase being determined by the rate at which the material passes through the solution.
Preferably the volume of the processing solution is less than 500 ml.
The method of the invention ensures that acceptable images can be obtained from the entire length of the film. Digital image processing time may be reduced by using the invention.
Lower volumes of processing solutions are used which leads to cost reductions.
The invention is easily applied to standard processing apparatus